JP2008166833A - Structure for degassing portion of electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for a degassing portion of an electronic component which is hardly generates a phenomenon that the entire ventilation portion of a bleed valve is covered by an electrolyte. <P>SOLUTION: A structure of a degassing portion of an electronic component has a container having a bleed valve for preventing the ingress of open air while releasing gas generated from a content, and an electrolyte and an electrode material laminate preserved in the container are provided. A projection is also formed that functions as a spacer which prevents the bleed valve from touching at the bottom face outside the bleed valve and prevents the ventilation portion of the bleed valve from coming into contact with an electrode material laminate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a structure of a degassing part of an electronic component, and particularly to a structure of a degassing part of an electronic component in which an electrode is immersed in an electrolytic solution.

  Electronic components such as electric double layer capacitors, batteries, and electrolytic capacitors have a configuration in which an electrolytic solution and an electrode material laminate are held in a container. Such electronic components may generate gas due to repeated charge and discharge. In that case, if the gas is not released to the outside, the pressure in the container rises, and there is a possibility that the sealing performance may be impaired or ruptured. Conventionally, various venting valves have been used to prevent intrusion of outside air while letting gas generated from the contents of the storage container escape.

  Patent Document 1 describes an electric double layer capacitor in which an exterior is formed of an aluminum laminate film, and an electrolytic solution that is a propylene carbonate solution and an activated carbon electrode are accommodated therein. A container made of aluminum laminate film is provided with a resin gas vent valve. The cross-sectional structure of the degassing valve is shown in FIG. The degassing valve 720 includes a pan-like main body 721 having a bottom hole 722 fused to an aluminum laminate film 715, a valve membrane 723 laid on the bottom surface, and a pressing member 724 provided on the valve membrane.

  The valve membrane 723 is operated by the pressure difference between the inside and outside of the container. That is, when the internal pressure of the container is lower than the external pressure, the valve membrane 723 sticks to the bottom surface and the bottom hole 722 is closed (FIG. 10A), and gas is generated and the internal pressure of the container becomes higher than the external pressure. It rises and discharges the gas to the outside (FIG. 10B).

  However, in this structure, both end portions of the valve membrane 723 are not always pressed against the bottom surface, and the bottom surface hole 722 is likely to be insufficiently closed over time. Further, this gas vent valve cannot prevent the electrolyte from flowing out from the bottom hole 722. Furthermore, it is necessary to cut out the container in accordance with the dimensions of the pan-like body at the time of attachment, and the attachment operation is complicated.

  FIG. 3 of Patent Document 2 describes a gas vent valve used for a similar electric double layer capacitor. However, this degassing valve has a complicated structure, a complicated mounting method, high cost, and poor production efficiency.

  The gas vent valve and the gas vent valve have a problem that when the vent inside the container comes into contact with the electrolyte, the electrolyte is taken out together with the exhausted gas. Therefore, for example, attempts have been made to cover the ventilation part with a gas permeable film and shield it from the liquid.

However, even in such a case, if the entire ventilation part such as the gas vent valve is covered with the electrolyte when the container is deformed, the air permeability is blocked or significantly inhibited.
JP 2003-297700 A JP 2003-272968 A

  The present invention solves the above-described conventional problems, and the object of the present invention is to provide a structure of a gas vent part of an electronic component in which a phenomenon that the entire vent part of the gas vent valve is not covered with an electrolytic solution hardly occurs. It is to provide.

The present invention relates to a degassing of an electronic component having a container having a degassing valve for preventing the intrusion of outside air while allowing gas generated from the contents to escape, and an electrolyte and electrode material laminate held in the container. Part structure,
The degassing valve has a protrusion functioning as a spacer on the bottom surface outside the degassing valve to prevent the vent of the degassing valve from contacting the electrode material laminate.
The structure of the degassing part of an electronic component is provided, and the said objective is achieved by it.

  FIG. 1 is a cross-sectional view showing the structure of a gas vent portion of an electronic component which is an embodiment of the present invention. This electronic component includes a container 10, an electrolytic solution (not shown) held in the container, and an electrode material laminate 2. A vent hole 11 is formed in the container 10, and a gas vent valve 4 is provided so as to cover the periphery thereof.

  The electrode material laminate 2 is, for example, a laminate of a collecting electrode 5 / working electrode 6 / separator 7 / working electrode 6 / collecting electrode 5. The electrode material laminate 2 has a fluorocarbon resin film 8 at a portion in contact with the gas vent valve.

  The fluorocarbon resin has liquid repellency. Therefore, if a fluorocarbon resin film is provided in a portion of the electrode material laminate that is in contact with the gas vent valve, the electrolytic solution is repelled, and the entire vent portion of the gas vent valve is not easily covered with the electrolytic solution. Here, the “portion in contact with the gas vent valve” does not always need to be in contact, and may be a location in the vicinity of the gas vent valve that can be contacted when the container is deformed.

  It is preferable to provide a protrusion (not shown) protruding toward the electrode material laminate on the bottom surface outside the gas vent valve. Such a protrusion functions as a spacer that prevents the vent of the gas vent valve from coming into contact with the electrode material laminate. Therefore, a space is formed between the ventilation portion and the electrode material laminate, and the entire ventilation portion of the gas vent valve is difficult to be covered with the electrolytic solution.

  In addition, on the bottom surface outside the gas vent valve, the film body covers the vent portion of the gas vent valve, and the adhesive portion is bonded so as to surround the vent portion of the gas vent valve. You may further have a gas permeable film.

  The electronic component as shown in FIG. 1 is manufactured as follows, for example. First, the collector electrode 5, the working electrode 6, and the separator 7 are formed into appropriate dimensions, and the collector electrode 5 is stacked in the order of the collector electrode 5 / working electrode 6 / separator 7 / working electrode 6 / collector electrode 5. In addition, the electrode material laminate 2 may be obtained by applying the collector electrode 5 on the working electrode 6 and drying it so as to overlap the separator 7. The fluorocarbon resin film 8 is affixed to a portion of the electrode material laminate 2 that is in contact with the gas vent valve, for example, a region sandwiched between collector electrode tabs. FIG. 2 is a perspective view showing an electrode material laminate on which a fluorocarbon resin film is attached. The fluorocarbon resin film 8 may be provided after the electrode material laminate 2 is wrapped with a protective sheet or the like.

  What is preferable as the fluorocarbon resin film 8 is an adhesive tape in which an adhesive layer is provided on one side of the fluorocarbon resin film. A commercially available adhesive tape may be used. The fluorocarbon resin film 8 may be used as a fixing material for bundling the laminate. Next, the electrode material laminate 2 is inserted into a container. Then, an electrolytic solution is poured into the container, and the seal port is heat-sealed to be sealed in a predetermined reduced pressure state.

  FIG. 3 is a sectional view showing a state in which a gas vent valve preferable for use in the present invention is attached to a container. The outer wall 10 of the container is provided with a vent hole 11 for escaping gas generated from the contents. The container is not particularly limited as long as it is a hermetically sealed container that requires regular degassing while preventing intrusion of outside air, and may be formed of a metal, a hard resin, a soft resin, or a composite material thereof. . For example, the container may be a plastic film, for example, a bag having a polyolefin film, and preferably an aluminum laminate film having a polyolefin film as an inner layer. This is because the polyolefin film is excellent in chemical resistance, particularly resistance to organic solvents. Among the polyolefins, polypropylene is preferable. This is true for the polyolefins described throughout the specification.

  The gas vent valve 31 includes a synthetic resin cup 32, a valve membrane 33, and a synthetic fibrous material 34. The material of the synthetic resin cup 32 may be a resin having sufficient rigidity to maintain the shape during use. In view of ease of molding and attachment, a thermoplastic resin is preferable. Polyolefin resins are particularly preferred because of their excellent chemical resistance. The resin cup 32 has a recess having a bottom hole 35 and a flange around the periphery of the recess, and also has an annular protrusion 36 surrounding the bottom hole 35. The protrusion 36 functions as a spacer that prevents the vent portion of the gas vent valve from contacting the electrode material laminate.

  A valve membrane 33 is laid on the bottom surface inside the recess so as to cover the bottom hole 35. The valve membrane 33 is made of a material that has elasticity and non-breathability and exhibits resistance to an organic solvent. Preferably it is rubber or the like. A synthetic fibrous material 34 is provided on the valve membrane 33. The synthetic fibrous material 34 is formed of a material having elasticity and air permeability and exhibiting resistance to an organic solvent. From such a viewpoint, a fibrous material mainly composed of polyolefin fibers is preferable. Examples of the fibrous material include fiber deposits, woven fabrics, nonwoven fabrics, and combinations thereof. A nonwoven fabric is preferable, and a nonwoven fabric with embossing formed on the entire surface is more preferable. The thickness of the synthetic fibrous material may be appropriately determined according to the opening pressure required for the valve.

  The synthetic resin cup 32 is bonded to the inner side surface of the container 10 at the flange portion so that the bottom surface inside the recess faces the hole of the container 10. The bonding method is not particularly limited, but when the inner surface of the container and the synthetic resin cup are both made of polyolefin, they may be fused. In the attached state, the adhesive portion of the synthetic resin cup 32 surrounds the vent hole 11 of the container so that the outside air does not touch the contents. In other words, the synthetic resin cup can be attached simply by positioning and bonding. However, the synthetic fibrous material 34 is vulnerable to heat and there is a concern that the elastic function is deteriorated. As a workaround, for example, a member formed of the same material as the synthetic resin cup 32 may be inserted between the container 10 and the synthetic fibrous material 34 as a heat insulating material (top plate 38).

  The synthetic fibrous material 34 is pushed by the inner surface of the container 10, the valve membrane 33 is pressed, and the bottom hole 35 is sealed. The synthetic fibrous material 34 can push the entire surface of the valve membrane 33, and the bottom hole 35 is reliably sealed. Synthetic fibrous materials with excellent chemical resistance are less likely to deteriorate in elasticity and have excellent sealing durability. The opening pressure of the valve can be easily controlled by changing the thickness of the synthetic fibrous material. In addition, the synthetic fiber material does not require handling in comparison with an elastic body such as a spring, and the assembly operation is very simple.

  FIG. 4 is a cross-sectional view showing a state in which a gas vent valve according to another embodiment of the present invention is attached to a container. The difference from the embodiment shown in FIG. 3 is that a gas permeable film 37 is provided on the outer side of the synthetic resin cup recess. By providing the gas permeable film 37, the liquid is not taken out together with the gas, and the liquid is prevented from entering the valve structure.

  The gas permeable film 37 has a characteristic of blocking a liquid and transmitting a gas, and is formed of a material exhibiting resistance to an organic solvent. From such a viewpoint, a continuous porous structure film of polyfluoroolefin is preferable.

  The gas permeable film 37 is bonded to the outer surface of the synthetic resin cup such that the film body covers the bottom hole and the bonding portion surrounds the bottom hole. Then, the liquid contained in the contents will not leak to the outside. When the synthetic resin cup material is polyolefin and the gas permeable membrane is a continuous porous structure film of polyfluoroolefin, the bonding method is a step of melting the synthetic resin cup material at the bonded portion, It is preferable to carry out by a method including a step of contacting and a step of quenching and curing the contact portion.

  Polyfluoroolefin is difficult to wet with liquid. Therefore, the adhesive or the molten resin does not adhere to the continuous porous structure film of polyfluoroolefin, and is difficult to adhere by a normal adhesion method or fusion method. According to the bonding method used in the present invention, it is considered that the melted polyolefin penetrates into the microporous structure of the polyfluoroolefin, and the polyolefin is cured in that state, thereby exhibiting an anchor effect and enabling strong bonding.

  Such a vent valve is excellent in blockage stability and chemical resistance and can reliably prevent the intrusion of outside air for a long period of time, so it can be suitably used by being attached to a container of a secondary battery or an electric double layer capacitor. . For example, in an organic electric double layer capacitor formed by immersing a carbonaceous electrode in an organic solvent, an organic solvent having strong erosion and leaching properties is used as a solvent for the electrolytic solution, and the chemical resistance, sealing property and liquid blocking property are improved. The superior vent valve of the present invention is particularly useful. Specific examples of such an organic solvent include ethylene carbonate, propylene carbonate, γ-butyrolactone, sulfolane, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, and acetonitrile.

  FIG. 5 is a cross-sectional view showing another example of a gas vent valve preferable for use in the present invention. This gas vent valve is composed of a synthetic resin base 51 and an umbrella-type valve membrane 52 which is an integrally molded product. In addition, the umbrella-type valve membrane 52 in FIG. 5 is shown as a partial sectional view.

  6A and 6B are a plan view and a cross-sectional view showing the shape of a synthetic resin base 51 which is a part of the gas vent valve in FIG. 3 and 4, the synthetic resin base 51 prevents the flange portion 53 for bonding to the inner surface of the container and the vent portion of the gas vent valve from coming into contact with the electrode material laminated body. The projection 54 functions as a spacer. The synthetic resin base 51 has a plurality of vent holes 55 arranged in a circumferential shape. This vent hole is closed by the umbrella-type valve membrane 52, and the inside of the container is blocked from outside air.

  FIG. 7 is a partial cross-sectional view of an umbrella-type valve membrane 52 that is a component of the gas vent valve of FIG. The umbrella-type valve membrane 52 is made of a material having elasticity and non-breathability and showing resistance to an organic solvent. A preferred material is rubber or the like. The umbrella-shaped portion 56 of the umbrella-shaped valve membrane 52 functions as a valve that prevents the outside air from entering while allowing gas generated from the inside to escape, and the spherical portion 57 of the shaft functions as a stopper for preventing the falling-off. The tip portion below the spherical portion 57 is a handle for incorporating the umbrella-shaped valve membrane 52 into the synthetic resin base 51, and may be removed after incorporation.

  The following examples further illustrate the present invention, but the present invention is not limited thereto.

  FIG. 8 is an exploded perspective view of the gas vent valve of the present embodiment. A 1 mm thick polypropylene plate (Mitsubishi Resin's “Rhombus plate” thickness: 1 mm) is press-molded to form a circular flat bottom recess having a bottom inner diameter of 4.5 mm, an edge inner diameter of 6 mm and a depth of 1.5 mm, and the periphery of the recess A polypropylene cup 62 having a flange portion having a width of 3 mm and an annular protrusion having a width of 0.4 mm and a height of 1.0 mm along the outer periphery of the bottom surface was formed on the bottom surface outside the recess. One hole 65 having a diameter of 0.5 mm was formed in the center of the recess. There is also a method of injection-molding pellets as a molding method.

  A PTFE (polytetrafluoroethylene) continuous porous structure film having a thickness of 0.3 mm (“PORFLON” manufactured by Sumitomo Electric Industries, Ltd.) was cut into a circle having a diameter of 5 mm. The obtained PTFE film 66 was placed on the outer surface of the polypropylene cup 62, and the temperature was raised to 200 ° C. for 5 seconds and held for 10 seconds with an impulse welder manufactured by Munekata Co., Ltd., and then rapidly cooled to room temperature in 10 seconds. As a result, the peripheral edge of the PTFE film 66 was bonded to the outer surface of the polypropylene cup 62.

  A rubber sheet (EPDM) having a thickness of 0.2 mm was cut into a circle having a diameter of 4 mm, and the obtained rubber sheet 63 was laid on the bottom surface inside the polypropylene cup 62. Next, a 0.8 mm thick polypropylene fiber nonwoven fabric (manufactured by Kmberly-Clark) having embossments with a diameter of about 0.5 mm formed on the entire surface at intervals of about 2 mm is cut into a circle with a diameter of 4 mm, and the rubber sheet 63 is This polypropylene fiber non-woven fabric 64 was overlaid to obtain a gas vent valve 61.

  This degassing valve was attached to the container to produce an electric double layer capacitor. FIG. 9 is a perspective view of the electric double layer capacitor of this example.

  First, an aluminum laminate bag 40 (manufactured by Dai Nippon Printing) having a polyolefin film on the inner layer of 14 cm in length, 11.0 cm in width, and 1.5 cm in width is prepared. Opened. The flange portion of the polypropylene cup was fused so as to surround the hole 41 from the inside of the bag 40, and the gas vent valve 61 was attached to the bag 40.

  An aluminum electrode, a carbonaceous electrode, and a separator, which were previously subjected to seal pretreatment on the lead electrode portion, were formed into appropriate dimensions to form an electrode material laminate as shown in FIG. The electrode material laminate was wrapped with the same material as the separator, and a fluorocarbon resin adhesive tape (manufactured by Nitto Denko) was attached to the region sandwiched between the collector electrode tabs 47. This was sandwiched between jigs and inserted into the bag 40. A propylene carbonate solution of tetraethylammonium tetrafluoroborate was poured into the bag 40 as an electrolyte, and the seal port was heat-sealed and sealed in a predetermined reduced pressure state to obtain an electric double layer capacitor.

  The electric double layer capacitor thus obtained can surely release the gas generated during manufacture or during use, and can prevent intrusion of outside air. In addition, even when the container is deformed, the phenomenon that the entire vent part of the gas vent valve is covered with the electrolytic solution hardly occurs, and the liquid is prevented from entering the valve.

It is sectional drawing which shows the structure of the degassing part of the electronic component which is one embodiment of this invention. It is a perspective view which shows the electrode material laminated body which affixed the film made from a fluorocarbon resin. It is sectional drawing which shows the state which attached the gas vent valve preferable to use for this invention to the container. It is sectional drawing which shows the state which attached the gas vent valve which is the other embodiment of this invention to the container. It is sectional drawing which shows the other example of a preferable venting valve used for this invention. It is the top view and sectional drawing which show the shape of the synthetic resin base which is components of the gas vent valve of FIG. FIG. 6 is a partial cross-sectional view of an umbrella-type valve membrane that is a component of the gas vent valve of FIG. 5. It is a disassembled perspective view of the degassing valve of an Example. It is a perspective view of the electric double layer capacitor of an Example. It is sectional drawing which shows the structure of the conventional gas vent valve.

Explanation of symbols

2 ... electrode material laminate,
4 ... Gas vent valve,
5 ... collector electrode,
6 ... working electrode,
7 ... separator,
8 ... Film made of fluorocarbon resin,
10 ... container,
11 ... vents,
31 ... Gas vent valve,
32. Synthetic resin cup,
33 ... Valve membrane,
34 ... Synthetic fiber material,
35 ... bottom hole,
36. Projection.

Claims (5)

A structure of a gas vent part of an electronic component having a container having a gas vent valve for preventing the intrusion of outside air while letting gas generated from the contents escape, and an electrolyte solution and electrode material laminate held in the container. There,
The degassing valve has a protrusion functioning as a spacer on the bottom surface outside the degassing valve to prevent the vent of the degassing valve from contacting the electrode material laminate.
Structure of the venting part of electronic parts. The gas vent part further includes a gas permeable film that blocks the liquid and permeates the gas, wherein the film body covers the vent part of the gas vent valve and the adhesive part is bonded so as to surround the vent part of the gas vent valve. And
The structure of the degassing part of the electronic component according to claim 1, wherein the protruding part prevents the film body from coming into contact with the electrolytic solution.   The structure of the degassing part of the electronic component according to claim 1 or 2, wherein the shape of the protrusion is an annular shape surrounding the ventilation part of the degassing valve. The vent valve is
A synthetic resin cup having a recess having a vent hole at the bottom and a flange portion at the periphery of the recess,
An elastic and non-breathable valve membrane laid on the bottom surface inside the recess to cover the bottom hole, and an elastic and breathable synthetic fibrous material provided on the valve membrane inside the recess,
Have
The synthetic resin cup is attached by being adhered to the inner surface of the container at the flange so that the bottom surface inside the recess faces the hole of the container,
In the attached state, the adhesive portion of the synthetic resin cup surrounds the hole of the container, and the synthetic fibrous material is pushed by the inner surface of the container, the valve membrane is pressed and the bottom hole is sealed. is there,
The structure of the degassing part of the electronic component in any one of Claims 1-3.   The structure of the degassing part of the electronic component according to claim 4, wherein the synthetic resin cup material is polyolefin and the gas permeable film is a continuous porous structure film of polyfluoroolefin.

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